In the known art, considerable favour has been found in the expedient of using caddies to manipulate packages having tubes in the production, control and packaging of yarn from textile fibre sliver. The caddies are located on belt conveyors or similar handling members serving the machine. The caddies individually move the packages and tubes to and from the processing units.
The caddies are provided with a vertical central mandrel which enables the package being carried to be maintained in an erect position not only during transport but also during preparation and unwinding. The packages are transferred and processed without being soiled or deteriorated since only the caddies are handled, and the caddies prevent the packages from contacting the machine members. A caddy is described in numerous documents of the known art, such as French patent 1,571,158 in the name of Giddings and Lewis-Fraser, Japanese No. JP-A-59-12128 in the name of Kanebo and Italian patent application 48,195/A/82 in the name of Murata. A drawback of the caddies of the known art is evident during the unwinding of the package in a bobbin winding machine. In this respect, it should be noted that in winding machines of the most recent design, the unwinding speed is on the order of 25 m/sec and more, with the yarn rotating about the package at a speed of approximately 10,000-20,000 r.p.m.
As a result of the relatively high speeds of rotation, radial stresses are generated which tend to move the package from vertical, and axial stresses are generated which tend to raise the package from the base. These stresses tend to shift the package and caddy from their correct vertically centered position during processing and unwinding, with possible misalignment of the caddy and separation of the package from the caddy mandrel on which it rests. To obviate these drawbacks, elaborate caddy constructions have been proposed which include resilient means for retaining the package on the mandrel and conical lead-in fins for centering the package. Such systems are mentioned in, for example, DE-A-4,236,038 and U.S. Pat. No. 5,297,761 in the name of Schlafhorst and in Italian patent application MI96A125 in the name of the present applicant. These arrangements are not, however, free from drawbacks, especially considering that in a yarn spinning and bobbin winding factory, thousands of caddies may be required for each machine, especially if processing several batches, i.e., dividing the bobbin winding machine by simultaneously using in some of the winding units a yarn different from that used in the other winding units of the same machine.